#LODD. It stands for line of duty death. It's used to describe the brave men and women who fall while serving their communities -- working to save others in times of need.

Russell Neary, 55, a lieutenant with the volunteer fire department in Easton, Connecticut, was killed on Monday night while responding to a call, according to CNN affiliate CTNOW.com. Debris blocked his truck's route on Judd Road; he was working to clear a path when a tree limb struck him.

"It was a line of duty death," Easton Fire Chief James Girardi told NewsTimes.com. "It's the first one we've ever had. And we're not over the shock of it. His death is a tremendous loss to his family, our department and the community."

NYPD officer Artur Kasprzak may have been off-duty on Monday night, but he was hard at work saving the lives of those in a house on Doty Avenue in Breezy Point, New York.

With flood water "surging" into his house, Kasprzak was able to shepherd six adults and a 1-year-old child into the attic, according to the NYPD spokesman James Duffy.

Around 7:30 p.m., he told one of the adults he was going back down to check the basement. When he didn't return, someone called 911.

"NYPD personnel from the Emergency Service and SCUBA units immediately responded to the residence using Zodiac boats and Jet Skis," the spokesman said, "but could not access the home due to down, electrified power lines in the water."

Officers discovered Kasprzak's body "unconscious and unresponsive" the next morning.

"If we would have had these things installed in the right places (in New York), they could have made a terrific difference," said Greg Holter of the Pacific Northwest National Laboratory. "The problem is we don't have a stock of things that we could put in place. It's not like we have a bunch of these sitting in a warehouse," Holter said. "It's a little frustrating really that we weren't at a better stage at this thing."

But DHS project manager John Fortune, while bullish on the plug, says the plug is not ready for prime time.

"This is an experimental prototype. This is something that is probably two years away or so" from real-world applications," Fortune said. "It would be like asking Apple, 'Why can't I have an iPhone 6 now?' Because it's somewhere in the lab now. It's not ready to go."

The plug -- simple in theory, but sophisticated in design -- inflates like a balloon to fit the contours of a tunnel, and can reduce leakage to amounts manageable by pumps. Placed on either end of some of the tunnels under New York's East River, the plugs could have prevented flooding, team members told CNN. But plugs would not have prevented water from infiltrating porous underground subway stations and other infrastructure, they said.

In all, seven New York subway tunnels and two commuter train tunnels flooded during Monday's record flooding. Some of the tunnels were flooded from track to ceiling and "it is still too early to say how long it will take to restore the system to full service," the Metropolitan Transit Authority, which operates the rail systems, said Wednesday.

The Department of Homeland Security began the "Resilient Tunnel Project" in 2007, focusing on the threat of terrorist gas attacks and fires in transit tunnels. But almost from the start, developers believed the technology could serve a dual purpose, protecting tunnels from floods during natural disasters.

DHS teamed with the Pacific Northwest National Laboratory, the University of West Virginia and ILC Dover, a private Delaware company, on the project.

An early scaled-down plug, consisting of a single layer, was effective at preventing smoke or gas penetration. But when the team used a stronger, single-layer plug in a full-scale inflation test, the fabric failed, sending the team "back to the drawing board," Fortune said.

The current plug consists of three layers, including a tough outer layer that consists of thick webbing made of Vectran, a liquid-crystal polymer fiber.

The plugs must be fitted to individual tunnels.

"When you look at these things, you get the idea of a kid's balloon," Halter said. But "they are not at all stretchable. They are specifically made to fit a tunnel of a specific dimension. They are tailor made. Their ability to expand or contract is less than 1%."

The plugs can be inflated in about three minutes. But once inflated, they are pressurized with either air or water.

"While we don't want to ride the back of a disaster, it's certainly our hope that people will look at this technology," Holter said. "This may be the worst storm ever recorded in the last 100 years, but that's no reason that we won't have another storm that will cause as much damage."

Should DHS have expedited development of the plug?

That's a hard question to answer, said terrorism expert Brian Jenkins, director of the National Transportation Security Center at the Mineta Transportation Institute in San Jose, California.

While officials can envision a wild spectrum of vulnerabilities, they have finite resources to address them, he said.

"There are lots of solutions that become obvious following a disaster of some type," Jenkins said.

"To a certain extent, security is almost always reactive, because it's hard to justify the costs of deploying technology for things that have not occurred. And once they do occur, it's almost impossible to resist spending the money on the technology to prevent a reoccurrence.